West Ham United's determination to strengthen their attack by signing Bayern Munich's Luca Toni and Eidur Gudjohnsen of Barcelona increased tonight as Luis Boa Morte suffered cruciate damage which could rule him out until the new year.

Boa Morte sustained the injury to his right knee during West Ham's 1–0 defeat by Tottenham Hotspur in the Premier League Asia Cup in Beijing. The club's chief executive, Scott Duxbury, and technical director, Gianluca Nani, had already decided to remain in Europe to pursue Toni and Gudjohnsen.

Boa Morte's fate leaves West Ham with only two senior forwards in Carlton Cole and the injured Dean Ashton, whose future is still unclear. Despite reports linking Stoke City with the 25-year-old there has been no official approach for the striker – who has a long-term ankle injury. The wearing of his No9 shirt by Junior Stanislas in China was because competition rules state all players must be numbered from 1 to 23, rather than a definitive sign of Ashton's imminent departure.

Duxbury and Nani decided to travel to two destinations in Europe rather than to Beijing, suggesting negotiations for Gudjohnsen or Toni or both may have reached an advanced stage. Gianfranco Zola is keen to sign an experienced striker with international pedigree as he seeks to improve on last season's ninth-place finish.

The club was downbeat over Boa Morte, who suffered the injury in what appeared an innocuous challenge with Benoît Assou-Ekotto. "Luis Boa Morte could be out until 2010 after suffering anterior cruciate ligament damage in his right knee," a statement said. "Boa Morte will undergo further tests to determine whether or not he will require surgery when the swelling on his injured knee goes down."

Zola was visibly upset. "It is a big blow for me," he said. "He is an important player both on the pitch and off the pitch."

Of the defeat to a late Jermain Defoe strike which the goalkeeper Robert Green iled to hold the Italian added: "[I am] not really [happy] but it is totally understandable. It is the first competitive game we have played this summer. I am going to use it as a good game to see the problems that we will work on so I will take it in a positive way."